Tuning for new converter?
Thread Starter
Launching!
Joined: Oct 2022
Posts: 206
Likes: 74
From: FL
Tuning for new converter? I just went from a stock tmbx converter to a 9.5" 2500 stall speed. My logs now show positive fuel trims with a positive hang at wot. Would a higher stall speed make it run leaner?
Thread Starter
Launching!
Joined: Oct 2022
Posts: 206
Likes: 74
From: FL
Fuel pressure is still the same.
It's a 5.3 with a small cam and 411 pcm, built 4L60E that's been strong for 9 months and still is doing great.
TECH Junkie
Joined: Jun 2008
Posts: 3,203
Likes: 1,391
From: Nitro Alley
Hopefully TruckDoug and/ or MaroonMonster can help out here.
They are great with Systems that work on OEM Hardware, like HP Tuners.
I personally walked away from Tuning OEM Control Modules (a long, long time ago) when I stopped offering Transmission Rebuilding and Engine Rebuilding Services.
I only build complete Power-Train Systems now (Engine, Trans, Transfer-Case, Diffs, Management Systems, Fuel Systems, and Electrical Systems) that run on Holley EFI.
On that NOTE...
I am actually working on my own Power-Train Management System and corresponding Electrical System.
If it works out (Fingers Crossed) I will be walking away from building Power-Trains...
I will ONLY be offering my Management and Electrical Systems (Universal for any Vehicle).
They are great with Systems that work on OEM Hardware, like HP Tuners.
I personally walked away from Tuning OEM Control Modules (a long, long time ago) when I stopped offering Transmission Rebuilding and Engine Rebuilding Services.
I only build complete Power-Train Systems now (Engine, Trans, Transfer-Case, Diffs, Management Systems, Fuel Systems, and Electrical Systems) that run on Holley EFI.
On that NOTE...
I am actually working on my own Power-Train Management System and corresponding Electrical System.
If it works out (Fingers Crossed) I will be walking away from building Power-Trains...
I will ONLY be offering my Management and Electrical Systems (Universal for any Vehicle).
Thread Starter
Launching!
Joined: Oct 2022
Posts: 206
Likes: 74
From: FL
Hopefully TruckDoug and/ or MaroonMonster can help out here.
They are great with Systems that work on OEM Hardware, like HP Tuners.
I personally walked away from Tuning OEM Control Modules (a long, long time ago) when I stopped offering Transmission Rebuilding and Engine Rebuilding Services.
I only build complete Power-Train Systems now (Engine, Trans, Transfer-Case, Diffs, Management Systems, Fuel Systems, and Electrical Systems) that run on Holley EFI.
On that NOTE...
I am actually working on my own Power-Train Management System and corresponding Electrical System.
If it works out (Fingers Crossed) I will be walking away from building Power-Trains...
I will ONLY be offering my Management and Electrical Systems (Universal for any Vehicle).
They are great with Systems that work on OEM Hardware, like HP Tuners.
I personally walked away from Tuning OEM Control Modules (a long, long time ago) when I stopped offering Transmission Rebuilding and Engine Rebuilding Services.
I only build complete Power-Train Systems now (Engine, Trans, Transfer-Case, Diffs, Management Systems, Fuel Systems, and Electrical Systems) that run on Holley EFI.
On that NOTE...
I am actually working on my own Power-Train Management System and corresponding Electrical System.
If it works out (Fingers Crossed) I will be walking away from building Power-Trains...
I will ONLY be offering my Management and Electrical Systems (Universal for any Vehicle).
Thread Starter
Launching!
Joined: Oct 2022
Posts: 206
Likes: 74
From: FL
The LTFT's are only off by 2 but my pet peeve is it hanging at WOT.
Think it could have been a knock sensor unplugged? I forgot about that. The second run I made down the test road here was just losing 10 degrees of timing. Not kr, not iat, or any other thing.
Those are set to mil on 2nd error. So it never set the light.
Since plugging that in the LTFT's are +1 in some areas.
I had to start the laptop back up to look at all the logs.
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TECH Junkie
Joined: Dec 2012
Posts: 3,620
Likes: 1,331
From: Iowa
you're changing how the engine is loaded and accelerates through the entire operational range.
It's not uncommon to need a bit of adjustment but it shouldn't be earth shattering amounts of changes
most everything will run fine untouched with a converter swap unless the change is totally drastic
That said...2% is enough to be just a slight variance in weather, or the fuel you get from station A instead of station B
if it's 2% to 4% everywhere in the range, then that 2-4% "stays" there when WOT...the controller is doing its job. LTFT adjust for things like differences in fuel or weather and apply that change to the whole map...even wot...so that at WOT the fueling stays accurate because factory controller uses narrow band sensors and will not adjust fueling at WOT because richer than stoich is being commanded.
Hope that makes sense
It's not uncommon to need a bit of adjustment but it shouldn't be earth shattering amounts of changes
most everything will run fine untouched with a converter swap unless the change is totally drastic
That said...2% is enough to be just a slight variance in weather, or the fuel you get from station A instead of station B
if it's 2% to 4% everywhere in the range, then that 2-4% "stays" there when WOT...the controller is doing its job. LTFT adjust for things like differences in fuel or weather and apply that change to the whole map...even wot...so that at WOT the fueling stays accurate because factory controller uses narrow band sensors and will not adjust fueling at WOT because richer than stoich is being commanded.
Hope that makes sense
Thread Starter
Launching!
Joined: Oct 2022
Posts: 206
Likes: 74
From: FL
you're changing how the engine is loaded and accelerates through the entire operational range.
It's not uncommon to need a bit of adjustment but it shouldn't be earth shattering amounts of changes
most everything will run fine untouched with a converter swap unless the change is totally drastic
That said...2% is enough to be just a slight variance in weather, or the fuel you get from station A instead of station B
if it's 2% to 4% everywhere in the range, then that 2-4% "stays" there when WOT...the controller is doing its job. LTFT adjust for things like differences in fuel or weather and apply that change to the whole map...even wot...so that at WOT the fueling stays accurate because factory controller uses narrow band sensors and will not adjust fueling at WOT because richer than stoich is being commanded.
Hope that makes sense
It's not uncommon to need a bit of adjustment but it shouldn't be earth shattering amounts of changes
most everything will run fine untouched with a converter swap unless the change is totally drastic
That said...2% is enough to be just a slight variance in weather, or the fuel you get from station A instead of station B
if it's 2% to 4% everywhere in the range, then that 2-4% "stays" there when WOT...the controller is doing its job. LTFT adjust for things like differences in fuel or weather and apply that change to the whole map...even wot...so that at WOT the fueling stays accurate because factory controller uses narrow band sensors and will not adjust fueling at WOT because richer than stoich is being commanded.
Hope that makes sense
It's that positive trim at PE that I hate, this engine seems really sensitive to wot PE. I'll get to it. On vacation this week might as well lol.
Thanks to you guys and everyone who replied.
TECH Apprentice
Joined: Nov 2016
Posts: 371
Likes: 18
From: switzerland
you're changing how the engine is loaded and accelerates through the entire operational range.
It's not uncommon to need a bit of adjustment but it shouldn't be earth shattering amounts of changes
most everything will run fine untouched with a converter swap unless the change is totally drastic
That said...2% is enough to be just a slight variance in weather, or the fuel you get from station A instead of station B
if it's 2% to 4% everywhere in the range, then that 2-4% "stays" there when WOT...the controller is doing its job. LTFT adjust for things like differences in fuel or weather and apply that change to the whole map...even wot...so that at WOT the fueling stays accurate because factory controller uses narrow band sensors and will not adjust fueling at WOT because richer than stoich is being commanded.
Hope that makes sense
It's not uncommon to need a bit of adjustment but it shouldn't be earth shattering amounts of changes
most everything will run fine untouched with a converter swap unless the change is totally drastic
That said...2% is enough to be just a slight variance in weather, or the fuel you get from station A instead of station B
if it's 2% to 4% everywhere in the range, then that 2-4% "stays" there when WOT...the controller is doing its job. LTFT adjust for things like differences in fuel or weather and apply that change to the whole map...even wot...so that at WOT the fueling stays accurate because factory controller uses narrow band sensors and will not adjust fueling at WOT because richer than stoich is being commanded.
Hope that makes sense
i find the original situation a bit weird, as positive closed loop stfts should carry over to wot/open loop and tend to make the engine run richer. (or was " the logs showing lean" in #3 not meant that way?)
Thread Starter
Launching!
Joined: Oct 2022
Posts: 206
Likes: 74
From: FL
When it has a negative fuel trim it will stop pulling fuel when it goes into PE so it doesn't go lean by continuing to pull fuel.
Last edited by LS299S10; Dec 4, 2022 at 03:32 PM.
TECH Junkie
Joined: Dec 2012
Posts: 3,620
Likes: 1,331
From: Iowa
are you verifying any of this with a wideband?
maybe the LTFT is doing exactly what they should be doing and you'll be benefitting at WOT when in PE from the trims being correct.
Even so...if your vehicle is SO sensitive that 2% is too much and throws off the car...then the tune is total garbage or something else is way off on the car
on the dyno and at the track, you can vary N/A WOT air-fuel by as much as a whole point and not see any drastic world changing differences in hp or timeslip
maybe the LTFT is doing exactly what they should be doing and you'll be benefitting at WOT when in PE from the trims being correct.
Even so...if your vehicle is SO sensitive that 2% is too much and throws off the car...then the tune is total garbage or something else is way off on the car
on the dyno and at the track, you can vary N/A WOT air-fuel by as much as a whole point and not see any drastic world changing differences in hp or timeslip
Thread Starter
Launching!
Joined: Oct 2022
Posts: 206
Likes: 74
From: FL
are you verifying any of this with a wideband?
maybe the LTFT is doing exactly what they should be doing and you'll be benefitting at WOT when in PE from the trims being correct.
Even so...if your vehicle is SO sensitive that 2% is too much and throws off the car...then the tune is total garbage or something else is way off on the car
on the dyno and at the track, you can vary N/A WOT air-fuel by as much as a whole point and not see any drastic world changing differences in hp or timeslip
maybe the LTFT is doing exactly what they should be doing and you'll be benefitting at WOT when in PE from the trims being correct.
Even so...if your vehicle is SO sensitive that 2% is too much and throws off the car...then the tune is total garbage or something else is way off on the car
on the dyno and at the track, you can vary N/A WOT air-fuel by as much as a whole point and not see any drastic world changing differences in hp or timeslip
Thats why the tune is total garbage.